1. Field of the Invention
The invention relates to a ceiling system, particularly a panelized ceiling system for a cleanroom or similar enclosure internal to another structure.
2. Description of the Related Art
There has recently been a steady rise in the use of cleanrooms as part of manufacturing in a variety of industries including, but not limited to, pharmaceuticals, microelectronics, biotech, food processing, surgical, and even painting applications. The need to avoid an inadvertent introduction of foreign particles into a resultant product is desirable in these types of industries to insure that the end product produced is safe, workable, and of consistent quality. In many microelectronic applications, for example, particles which are not visible to a human eye can get into a manufacturing process and render the resultant product completely inoperable. In pharmaceuticals and food preparation, an inadvertent introduction of contaminants can make the products poisonous or undesirable to use, in addition to resulting in violations of required manufacturing standards.
Most cleanrooms are generally constructed internal to other buildings or structures, and the use of such internal cleanrooms is becoming highly desirable as they are often cheaper, easier to construct, and use than having entire “clean buildings,” In its most general form, building an internal cleanroom simply requires that a portion of the internal volume of the initial structure be sealed off from the resultant environmental of that structure. This portion is then supplied with its own air handling and filtration systems which serve to remove particles and the like from the air. Air is constantly flowed into the cleanroom from air handling devices which constantly remove pollutants from the environment in the form of or air suspended material using filters and related technologies. The filtered air is then returned to the internal volume of the cleanroom and cycles through again. In this way, the air is both originally clean, and is then constantly scrubbed to continually remove any introduced particles. The constant air motion also serves to move newly introduced particles away from work areas and into filters to further protect the delicate work.
Certain cleanrooms are not as concerned with particulate presence as they are with general cleanliness. These cleanrooms are designed to be repeatedly cleaned and disinfected to keep them free from the introduction of germs and other biologicals which contaminate the processes. In particular, in many pharmaceutical manufacturing processes, the introduction of a particulate on its own will not necessarily effect the resultant pharmaceutical's effectiveness, but introduction of an algal spore or virus could produce an allergic reaction in the user or even damage the product.
Traditionally, cleanrooms have been constructed of modular upright panels which form walls. These panels may then be attached to existing floors or ceilings to form the cleanroom. For more demanding applications, existing structures are not used and the clean room has an introduced floor and ceilings effectively suspending the clean room's internal volume. These constructed floors and ceiling are used as many traditional construction materials are sufficiently porous to allow an overly large amount of air to enter the clean room environment which can be prevented by using such constructed systems.
Ceilings in a cleanroom have traditionally been constructed by providing a ceiling grid which comprises a series of beams which are connected together to form a grid frame having a number of openings therethrough. Ceiling panels are then placed in each of the openings, such as on the arms of an inverted “T” shape located on the grid to form the ceiling. To provide for sealant of the panels to the grid, the grid will often have troughs formed on the inside of the arms of the T which include a gel sealant, placed in the trough in a low viscosity state. The gel is then allowed to increase in viscosity and fill the trough. Each panel then includes a knife-like edge which is pressed into the gel to form a tight seal between the panel and the grid. This seal is generally airtight and serves to seal the room.
While these systems work in many clean room applications, in some of the most demanding “clean” applications, they are unsuitable because the design necessarily creates cracks and crevices in the resultant ceiling of the cleanroom. The cracks and crevices can harbor contaminants such as mildew, even if the ceiling is cleaned regularly. This is particularly problematic in the gel based sealing system because the gel itself can attach to particulates which become difficult to remove because they are attached to the gel.
There are some grid systems designed to try and reduce and/or eliminate these cracks and crevices by providing for a flush internal surface of the ceiling of the cleanroom. These systems, however, and still dependent on the grid type of construction leaving a number of cracks in the ceiling.